Gastritis is inflammation of the lining of the stomach; chronic gastritis can lead to an ulcer. Helicobacter pylori is one common cause of gastritis, but this inflammation can also be caused by NSAID use, alcohol or autoimmune diseases. The symptoms of gastritis and an ulcer are the same: a burning, gnawing pain in the upper abdomen with a loss of appetite. Gastritis causes milder and shorter-lived pain as compared to an ulcer.